Automatic transfer switch (ATS) systems are widely used to control the delivery of power from different power sources to a load and, in particular, used to control which one of a set of power sources provides power to the load at a given time.
ATS systems can be employed in a variety of situations, both commercial and residential. For example, a private residence normally receives its electrical power from a utility company. For various reasons, however (e.g., location in a region prone to severe weather), the homeowner can desire a back-up source of electrical power, so that comfort or at least habitability of the residence can be maintained, during periods in which utility power is unavailable.
Typically, a gasoline, diesel, propane or natural gas internal combustion engine-powered electrical generator, capable of generating three-phase power, is installed in or near the residence, and arranged (in a split-phase alternating voltage manner) to be connected to one or more of the electrical circuits in the residence in order to provide the desired back-up power. However, one cannot simply leave the back-up generator permanently connected, in parallel with the utility power, to the residential electrical circuits. Nor can one simply power up a back-up generator and connect it to the residential electrical circuits, without first disconnecting the residential circuits from the power lines coming in from the utility.
To effect the proper switching of the residential electrical circuits (or other load) from the utility to the back-up generator (and eventually back again to the utility), transfer switch systems can be employed. While manual transfer switch systems are available, ATS systems have become popular insofar as an ATS system is able to automatically switch from one power source (e.g., the utility) to another power source (e.g., the back-up generator) whenever the system detects that the one power source is not properly providing power, without the presence of a human operator.
ATS systems commonly employ relays, microprocessors and/or other internal components such as application-specific integrated circuits that make it possible for the ATS systems to provide their desired automatic functionality. To operate, these internal component(s) require power. Typically, this power must meet one or more criteria. For example, the internal component(s) may require power having a particular voltage level such as 12 Volt DC power or 5 Volt DC power.
The power for the internal components of an ATS system typically is provided from one of the power sources that are coupled to the ATS. The power sources that are coupled to a given ATS system can vary significantly in terms of the characteristics of the power that is output by the power sources to the ATS system. For example, the actual voltage levels of different power sources that can be coupled to an ATS system can vary significantly, e.g., from 0 Volts AC to near 600 Volts AC. Commonly, transformers or other power conversion devices are employed (typically, externally of the ATS system) to convert the voltage levels of the power sources to the levels required by the internal components of the ATS system.
Because different power sources can differ significantly from one another in terms of the characteristics of the power they provide, the external transformers or other conversion devices employed in conjunction with any given ATS system must be properly tailored for use with the specific power sources with which that ATS system is intended to be used. Consequently, once the ATS system is configured for operation, in conjunction with one or more of these external conversion devices, the ATS system can only operate in conjunction with the specific power sources that correspond to the selected external conversion devices. While the particular external conversion devices can be changed to allow the ATS system to operate in conjunction with other power sources, this typically requires the purchase of additional expensive components, or the expensive reconfiguration of the conversion devices.
Further, as discussed above, ATS systems are utilized because there are circumstances in which characteristics of the power delivered by any given power source will vary. To the extent that such variations occur, external transformers or other conversion devices that are designed to receive and process power meeting specific characteristics may no longer provide power satisfying the requirements of the ATS systems or otherwise not work properly. Again, to keep the ATS systems working properly, it may be necessary to obtain expensive additional components or perform expensive reconfigurations.
Additionally, if the power provided by a given power source varies to such an extent that proper power can no longer be provided to the internal components of the ATS system, it will be necessary for the ATS system to switch in its operation so that power from an alternate power source can be provided to the internal components. Thus, special switching components are needed within the ATS system to guarantee that an appropriate one of the power sources is providing power to the internal components of the ATS system at any given time.
It would therefore be advantageous if a new ATS system could be designed that was capable of receiving, from a variety of different types of power sources, power having a variety of different characteristics and, in response, capable of supplying power to the internal component(s) of the ATS systems, where the characteristics of the supplied power met the power requirements of the internal components. Additionally, it would be advantageous if such an ATS system did not require the use of external transformers or other conversion devices, particularly the use of such devices that were especially configured for operation in conjunction with certain power sources.
Further, it would be advantageous if such an ATS system could continue to provide power to its internal components that met the power requirements of those components, even when characteristics of the power being provided to the ATS system by the power sources varied over time. Additionally, it would be advantageous if such an ATS system was not significantly more complicated or expensive to implement than conventional ATS systems.